Well i respect your query but to let you know that you are at the community for HR Professional and you must put these kind of queries to any investment or financial advisory website/community. But I can say something in this regard with due respect to my knowledge.
Well as you have NSC bond(s) which is/are near to maturity, so now you just need to visit your local post office and collect a maturity bond/ redemption form and complete the procedure accordingly. You can get complete procedure written on the form else can consult the department (Post Office) if you want.
Second, can visit to the website
India Post | Financial Services | POSB | National Savings Certificates (NSC) <link updated to site home> where you can also get the information and procedure to follow in this regard